[1] It was released on August 30, 2019, her thirtieth birthday, through Warner as a promotional single.

On August 12, 2019, Rexha confirmed the song's title and release date.

[4] "Not 20 Anymore" is a "jazzy, slow-burn" ballad[5] about body acceptance and self love.

[5] Mike Wass, writing for Idolator, wrote that the song "takes a powerful stance against ageism".

[8] The video also features a series of 20 year-old men and women giving their own testimonials about what it feels like to be that age, including the fears, insecurities and worries about the future that come with youth.